Exchanges like the CBOE are so-called self-regulatory organizations, charged with enforcing rules for trading by their member firms.

The SEC said the CBOE failed, among other things, to prevent abusive short-selling by a member firm. Short-sellers bet against a stock. Regulators say excessive short-selling targeted at weak companies can push them into collapse and fan market volatility.

The alleged failures occurred from 2008 to 2012.

The CBOE agreed to take corrective action but neither admitted nor denied wrongdoing.